1. Field of Invention
The present invention relates generally to pneumatic tires and more specifically to pneumatic tires designed to be used primarily off the road, and even more specifically to farm tires.
2. Description of the Related Art
Pneumatic tires designed primarily for off-the-road use often feature an "open" tread pattern with a lower net-to-gross ratio than tires intended for highway use. Off-the-road tires also commonly feature laterally extending tread lugs which cut into the loose ground surface. The subject invention features such a tread, some aspects of which are discussed in U. S. Pat. No. 4,711,283.
Pneumatic tires have featured various devices to protect the sidewall area of the tire from damage. One such device, a scuff rib, is a continuous rib of rubber which protrudes axially outward from the sidewall to be protected. Some tires feature a "broken" or "interrupted" scuff rib which is not continuous but performs a similar function. Examples include U. S. Pat. No. 2,800,098, French Application No. 2,159,267, German Application No. 738,045, and French Application No. 2,095,395. Occasionally tire treads feature axially extending lugs to improve traction in snow or in loose dirt. Such lugs are commonly found on farm tires. Often, sidewall protrusions on such tires are located axially outward of the lateral edges of such lugs as seen in U.S. Pat. No. 3,457,981. Occasionally, the sidewall protrusions are located axially outwardly of the portion of the inner tread surface interposed between the tread lugs as in British Design Patent No. 1,000,465. Under some conditions, the sidewall protrusions have caused cracking in the sidewall area, leading to premature failure of the tire.